Luigi, I doubt that you would find a cheaper way to record, but are you doing only voice?
If you are, then you may consider some formats more compatable with those who may be doing your music. Likely they will send a cd, or dat tape.
If you will be doing music as well, then you will need a more complex setup. A c-3000 is a good mic, and I think it will suit the voices fine, assuming that you pay proper attention to your room acoustics. You will also want to make or purchase a "pop" screen or a windsock. This will keep the boomy pop noises from reaching the mic, and make the track sound cleaner as a result.

Thanks for the advice Steve.

Well I intend to do commercials with voice-over music (mainly instumental sounds).

My main worry is not the music track but mainly the voice (warmth, clarity, depth, etc.). We have good voices, but they seem "dry" and doesn´t stand out in the commercials.

Please advise if these two products would be sufficient for these specific needs.

Thanks once again for your precious help.

Luigi, I think what Steve is trying to say is that the Roland just isn't very widely used in professional realms, and to be able to accept and deliver material in more common formats, you should possibly consider some other options. If you are only required to record the material, and then deliver that voice material to another facility to be mixed with music and FX, you'll probably need to output to either CD (data or audio; does the Roland unit you specified burn to CD?) or DAT. If you will be mixing the voice with music and FX, then I would suggest a computer based DAW with extensive editing, mixing, and CD burning capabilities, and a good DAT machine as well, as many projects will appear on DAT, and you need to be able to deal with that. I've never heard a C3000 in a VO application, so I can't speak to that, and I wish I knew more about the Roland unit you're looking at. Working in audio/video and dealing with VO on a daily basis, though, I do second what Steve said in looking at a setup that allows you greater flexibility and compatibility with other facilities than a proprietary stand alone unit. Just my $.02.

Your mic and multitrack are probably fine. Most voice-over work you hear on the radio is compressed. Be careful though with it. Use a low ration (2 to 1 is a safe bet,) a low threshold, say -20 db (assuming your are peaking well above that). Attack should be fast and release should be pretty fast (usually means turning the knob left).

You'll find the voice wont have to compete with the music beds or other background sounds as well as grab your attention more.

I just realized i said ration instead of ratio. Oops.

But yeah, I've actually done some voice work with the AKG 3000b and had good results. Compressors make a big difference on voice overs. I've done a pretty good deal of radio production so I'm not just talking out of my ass.

With respect to jbuntz's comments on compression, you should know that this "overall compression" won't have a drastic impact on your audio. What you need to be more concerned with is the quality,and sound of your mixes. I don't know exactly what your issues is with the vocals "not standing out", but I do have a couple of suggestions for you.
You can try an enhancer. This is a device that will boost the presence of both the bottom, and top end of a sound, in proportion to the volume input to the device. You can make the vocals crisper, and more defined, while adding body at the same time.

Also, you could put the vocals, and mix, through a 2ch compressor that has a side chain function, and use the vocals to key the music. However much gain you select on the compressor, will be applied to the music, each time the voice comes in. This is an effective auto volume control for your mix, so that the vocals will stand out more.
Finally, you could use a VERY small amount of reverb, and eq it so only the shhh sounds are audible. This will give the vocals a shiny kind of finish, and can also help to draw attention to them.

Steve.